Older adults arrive in the neurological clinic with a variety of complaints about their changing cognitive profile. These include reduced interest in hobbies and activities, repeating stories and statements, trouble learning how to use new tools and appliances, difficulty keeping track of what day it is, and difficulty remembering appointments. Such complaints have a striking feature in common: They all appear to be related to one's mental representation of "what is happening now." Recent research in cognitive psychology and neuroscience has begun to explain how people construct such representations and update them to facilitate perception and memory. This research suggests that the segmentation of ongoing activity into meaningful events is crucial to later memory for those events. However, little is known about how these mechanisms change with aging and dementia. The specific aims of this research address this lacuna: Specific Aim 1: Identify cognitive mechanisms of effective event segmentation. What distinguishes those individuals who segment events effectively from those who do not? Does this change across the lifespan? The proposed research will address these questions using psychometric and functional and structural neuroimaging methods. Specific Aim 2: Assess the contribution of effective event segmentation to memory in older adults. In younger adults event segmentation is associated with updating the current contents of short-term memory and with long-term memory retention. The proposed research will investigate how the relations between event segmentation, online memory updating and long-term memory change with age using behavioral and neuroimaging methods. Specific Aim 3: Test interventions to facilitate effective encoding of events. To the extent that effective event segmentation helps memory, improving event segmentation may improve memory. The proposed research will test interventions intended to improve memory by facilitating effective event segmentation. This research proposed here is all based on tasks in which observers comprehend and remember movies and stories that are closer to real-life activity than typical laboratory materials. The tasks are not too different from everyday comprehension of ongoing activities and conversations. These features improve the chances that this approach to event perception and memory may generalize to the memory complaints common to older adults. PUBLIC HEALTH RELEVANCE: Declines in memory for everyday events are one of the common complaints of aging. Recent research with younger adults suggests that "chunking" ongoing activity into meaningful events is important for later memory. The proposed research investigates how the mind and brain do this chunking, how it changes as people age, and what interventions might improve its effectiveness.